HT4100 4.1, 4.5, 4.9 Discussion, newbie need help in Cadillac Engine Technical Discussion; would appreciate any feedback on the following. i have a 90 seville 4.5 with 65k. the car runs great, good ...

newbie need help

would appreciate any feedback on the following. i have a 90 seville 4.5 with 65k. the car runs great, good acceleration, no missing. recently replaced o2 senser, catalitic converter, plugs,air filter,fuel filter. Now the problem is , on inclines ,going up steep hills. i get poor performance, no missing, just no power,car will hardly do 50 mph. seems to be worse with the a/c on ,will bogg down to 30/40 mph. HELP!!!!!! Thanks.